/Engine/Source/Runtime/Engine/Public/AnimEncoding.h
Utility function to determine the two key indices to interpolate given a relative position in the animation
The rate at which to interpolate the two keys returned to obtain the final result.
static float TimeToIndex ( float SequenceLength, float RelativePos, int32 NumKeys, EAnimInterpolationType Interpolation, int32 & PosIndex0Out, int32 & PosIndex1Out )